Why interhalogens are more reactive than halogens ?

Answer

### Step-by-Step Solution:

1. **Understanding Interhalogens**: Interhalogens are compounds formed between different halogens, represented as XY, where X and Y are different halogen elements (e.g., ClF, BrCl).

2. **Bond Strength in Interhalogens**: The bonds in interhalogen compounds are generally weaker compared to the bonds in pure halogen molecules (XX). This is due to the differences in electronegativity between the two different halogens involved in the interhalogen compound.

3. **Polarity of Interhalogen Bonds**: Interhalogen compounds are also more polar than pure halogen compounds. The difference in electronegativity between the two different halogens leads to a significant dipole moment, making the bond more polar.

4. **Energy and Stability Relationship**: There is an inverse relationship between energy and stability. Higher energy indicates lower stability, while lower energy indicates higher stability. Since interhalogen bonds are weaker and more polar, they possess higher energy compared to the stronger, non-polar bonds in pure halogens.

5. **Reactivity Correlation**: Since higher energy corresponds to higher reactivity, interhalogens, which have weaker and more polar bonds, are more reactive than the halogens themselves. This means they can more readily participate in chemical reactions.

6. **Conclusion**: Therefore, the greater reactivity of interhalogens compared to halogens can be attributed to the weaker and more polar bonds in interhalogen compounds, leading to higher energy and lower stability.